(CBS NEWS) -- The fireworks began early at Thursday night's vice presidential debate in Danville, Ky., with Vice President Joe Biden and Republican vice presidential nominee Rep. Paul Ryan hammering each other -- and the men at the top of their ticket -- over the attacks in Libya and other foreign policy issues.

"It took the president two weeks to acknowledge that this was a terrorist attack," Ryan claimed, before criticizing the Obama administration for "projecting weakness abroad."

"What we are watching on our tv screens is the unraveling of the Obama foreign policy," he added.

Biden, who smiled incredulously during Ryan's comments, responded, "With all due respect, that's a bunch of malarkey."

He criticized Ryan for voting to cut funding for embassy security and added of Mitt Romney and Ryan, "These guys bet against America all the time."

For Biden, the debate marked an opportunity to change the narrative of the campaign in the wake of President Obama's widely-panned performance in the first presidential debate last week. Mitt Romney has gained in both national and battleground state polls in the wake of that performance, and the two men are now effectively tied in national polls. While vice presidential debates have not changed the course of a campaign in the past, a strong performance by the vice president could allow the Obama campaign to regain its footing.

For Ryan, the Wisconsin Republican congressman and House Budget Committee chair who is seen by many as the intellectual leader of the GOP, the debate was a chance to introduce himself to the American people and make a forceful case for the Romney/Ryan ticket. Ryan, who asked to be referred to as "Mr. Ryan" instead of "Congressman Ryan" by the moderator, was pressed on his plan to transform Medicare into a voucher-like system as well as the Romney-Ryan ticket's unwillingness to specify which deductions and loopholes should be eliminated from the tax code in order to make its tax cuts revenue-neutral.

The 90-minute debate at Centre College, moderated by ABC News' Martha Raddatz, was split between domestic and foreign issues. The two men were seated - unlike last week's presidential debate - and the debate was broken into nine 10-minute segments.

On Iran, the two agreed Iran should not be allowed to obtain a nuclear weapon, but Ryan said sanctions should be tougher claiming Iran is moving faster toward a nuclear weapon. Biden defended the administration's sanctions saying "These are the most crippling sanctions in the history of sanctions. Period."

Biden followed by asking, rhetorically, how the administration could make the sanctions any tougher. "What more can the President do? We will not let them acquire a nuclear weapon," he said.

Raddatz then moved on to domestic policy where Biden and Ryan got to Mitt Romney's comment at a Florida fundraiser that "47 percent" of people don't pay income taxes. Ryan came to his running mate's defense, "sometimes the words don't come out of your mouth in the right way," Ryan said.

Biden immediately dismissed the suggestion that Romney's "47 percent" was a flub saying, "If you think he just made a mistake, then I've got a bridge to sell you."

Moving to Medicare, Biden laid down his commitment, "We will be no part of a voucher program or the privatization of Social Security," he said. But Ryan accused the vice president of not putting "a credible solution on the table."

Raddatz then moved on to the proposed tax plans of both the Obama-Biden and Romney-Ryan ticket. Ryan fiercely defended Romney's plan saying "six studies have guaranteed that this math adds up," and guaranteeing that his plan won't raise the deficit or raise taxes on the middle class.

On the topic of abortion, Raddatz asked Ryan if someone who wishes abortion to remain legal has something to worry about with Romney in office.

"We don't think that unelected judges should make this decision," said Ryan

But Biden argued those who wish abortion to remain legal do in fact have something to worry about, "The next president will get one or two supreme court nominees, that's how close Roe vs. Wade is," he said.

On a personal note, Raddatz asked what each candidate's individual character would bring to the White House. "There are plenty of fine people who could lead this country," Ryan began, "but what you need are people who, when they see problems, fix those problems."

Biden pointed to his drive to fight for the middle class. "My record stands for itself," he said, "I never say anything I don't mean...my whole life has been devoted to leveling the playing field for middle class people."

In closing, Biden reiterated his commitment to the middle class once more, "The president and I are not going to rest until the playing field is leveled," he said, "That's what this is all about."

Ryan, with the final word, made the hard sell, "Mitt Romney and I will not duck the tough issues, and we will not blame others for the next four years. We will take responsibility...the choice is clear, and the choice rests with you, and we ask you for your vote."

Following the debate, President Obama made a phone call to Vice President Biden to congratulate him on his debate performance. Touching down at Andrews Air Force Base after his campaign trip to Florida, Mr. Obama told reporters, "I thought Joe Biden was terrific tonight. I could not be prouder of him. I thought he made a very strong case and I really think that his passion for making sure that the economy grows for the middle class came through. So I'm really proud of him."

Meantime, Romney placed a congratulatory phone call to Ryan as well. According to campaign spokesman Rick Gorka, Romney told Ryan "to say 'hello' to his wife Janna and his family for him and that they should be proud of his debate performance."